Patterns of host use in Culex mosquitoes and their implications for arbovirus transmission dynamics in urban environments.

Understanding mosquito (Diptera: Culicidae) feeding behaviour is essential for assessing arbovirus transmission risk. Culex mosquitoes are key vectors, yet their host-feeding patterns in urban areas of South America remain understudied. This study examined the blood-feeding patterns of four Culex species in Córdoba, Argentina, emphasizing overall trends, seasonality and host preferences. Mosquitoes were collected during spring, summer and autumn across four urban sites over a 2-year period (2017-2018). Blood meals were identified through molecular analysis. Culex dolosus fed exclusively on birds, while Cx. interfor Dyar, Cx. saltanensis Dyar and Cx. quinquefasciatus Say fed on both birds and mammals. Culex quinquefasciatus accounted for most identified blood meals (n = 219), with 83% derived from birds and 17% from mammals. The most frequently detected local avian hosts were Zenaida auriculata (24.5%) and Passer domesticus (10%), while the most common mammalian hosts were Canis lupus familiaris (14.5%) and Homo sapiens (13.6%). Bird-derived blood meals predominated in all seasons. Forage ratio estimates indicated that Cx. quinquefasciatus exhibited a preference for P. domesticus, Agelaioides badius and C. lupus familiaris. These results highlight key vertebrate hosts potentially involved in local transmission cycles, with Z. auriculata and P. domesticus emerging as important nodes for arbovirus maintenance in urban Córdoba.